Green-synthesized ZnO nanoparticles for efficient atrazine detection: electrochemical and computational investigations

Developing sustainable and efficient methods for detecting environmental contaminants like atrazine (ATZ) is critical for environmental monitoring. This study uses a green approach to synthesise zinc oxide nanoparticles (g-ZnO NPs), employing an aqueous extract of <i>Haldina cordifolia</i> leaves as a natural reducing and stabilizing agent. The synthesized g-ZnO NPs were characterized using techniques such as XRD, TGA, SEM, UV-Vis spectroscopy, XPS, and FTIR to confirm their crystalline structure, morphology, optical properties, and functional groups. These nanoparticles demonstrated excellent sensitivity for the detection of ATZ, a widely used herbicide, <i>via</i> an electrochemical approach. The molecular docking simulations also predicted a favourable affinity of ZnO towards ATZ <i>via</i> hydrogen bonding. The sensor developed exhibited high selectivity for ATZ detection, achieving an LLOD of 0.41 μg mL^-1 within a linear range of 0.5 to 3 μM. Its practicality was validated in different types of water where the recovery rates ranged from 87.26% to 94.8% in STP water and from 90.52% to 95.66% in DI water, highlighting their reliability in real-world applications. In this study, <i>Haldina cordifolia</i> is being explored for the first time to synthesize g-ZnO NPs, which are then utilized for the electrochemical detection of ATZ. The biosynthetic approach not only provides an eco-friendly route for nanoparticle synthesis but also enhances the potential for rapid and reliable detection of ATZ in water and STP samples.